I used Cloudflare Tunnels for a project that had hundreds of tunnels did roughly 10GB/day of traffic entirely for free. The project has since moved to Cloudflare Enterprise, where the project pays the opposite of free, but was completely expected as the project grew.

I'm pretty sure Tunnels supports RDP and if you don't use a ton of bandwidth (probably under a 1TB/mo), Cloudflare probably won't bother you.